Mitigating the capacity and voltage decay of lithium-rich layered oxide cathodes by fabricating Ni/Mn graded surface

Lithium-rich layered oxides (LLOs) deliver a high energy-density of above 1000 W h Kg −1 owing to new charge/discharge mechanisms and are regarded as up-and-coming cathodes for next-generation lithium-ion batteries (LIBs). However, they usually suffer from serious capacity and voltage decay during r...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2017, Vol.5 (47), p.24758-24766
Main Authors: Li, Feng, Wang, Yangyang, Gao, Shilun, Hou, Peiyu, Zhang, Lianqi
Format: Article
Language:English
Subjects:
Batteries
Cathodes
Chemical precipitation
Decay
Electric potential
Electrochemical analysis
Electrochemistry
Electrodes
Energy
High voltage
Lithium
Lithium-ion batteries
Manganese
Nickel
Oxides
Rechargeable batteries
Salts
Voltage
X ray photoelectron spectroscopy
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Summary:Lithium-rich layered oxides (LLOs) deliver a high energy-density of above 1000 W h Kg −1 owing to new charge/discharge mechanisms and are regarded as up-and-coming cathodes for next-generation lithium-ion batteries (LIBs). However, they usually suffer from serious capacity and voltage decay during repeated cycles, limiting their wider practical applications. Herein, Ni/Mn-graded LLOs, in which the nickel content increases gradually, while the manganese content decreases continuously at the outer surface of secondary particles, were rationally designed and further prepared by a modified co-precipitation route combined with solid-state reactions. As expected, this Ni/Mn-graded LLOs exhibited a higher reversible capacity of 290.9 mA h g −1 , much improved stability of the capacity and voltage, ∼90% capacity retention, and a high voltage of 3.23 V ( vs. Li/Li + ), even after 200 cycles, compared with the normal LLOs. XPS and XRD characterization of the cycled electrodes indicated that these enhanced electrochemical properties are probably ascribed to the nickel-increased surface, which suppresses the structural transitions from layered to spinel, and/or the rock-salt phases as well as the side-reactions on the electrode/electrolyte interface. In particular, this Ni/Mn-graded structure opens up a feasible and effective tactic to mitigate the capacity and voltage decay of LLOs and could possibly promote the process of their practical application in high-energy LIBs.
ISSN:2050-7488
2050-7496
DOI:10.1039/C7TA07659B